What is state capacity and how does it affect development? The concept of state capacity acquired centrality during the late seventies and eighties, sponsored by a rather compact set of scholarly works. It later permeated through several disciplines and has now earned a place within the many governance dimensions affecting economic performance. The present article aims to provide a historical account of the evolution and usage of the state capacity concept, along with its various operationalizations. It examines in particular: a) the growing distance in the usage of the concept by different disciplinary and thematic fields; b) the process of `branching out’ of the concept from restricted to more multidimensional definitions; c) the problems with construct validity and concept stretching, and d) the generalized lack of clarity that exists regarding the institutional sources of state capacity.